The present invention is related to a method for manufacturing a roller shaft of a computer character-cutting device and to the roller shaft itself, and especially to a method to directly and tidily connect an engaging belt with the roller shaft by laser welding, it suits various rollers or roller shafts of paper feeders and their method of manufacturing.
FIG. 1 shows a conventional roller 10, wherein, the surface thereof has toothed grains 11 which are formed by direct embossing on the roller 10 and then by surface curing to get the standard hardness of the desired product. Wherein, in the surface curing process, the tooth tips mutually engaging will be slightly dulled; and direct processing on the roller has larger difficulty, after using a period of time, engaging force will be dulled by continuous abrading, this is a very undesired situation.
In order to solve the defect of the conventional roller shaft of a character-cutting device, there has been another roller (as shown in FIG. 2) composed of a roller axle 20, an external sleeve 21 and an engaging belt 22. The thin steel sheet forming the engaging belt 22 is etched to have sharp slim tooth grains on the surface of the thin steel sheet for wrapping around and spot welding to the external sleeve 21, the two ends of the external sleeve 21 spot welded to the engaging belt 22 are stuck to the roller axle 20.
Such a roller can increase frictional braking force of the surface of the roller, but the joint on the engaging belt 22 is combined by spot welding, accuracy of positions of the spots 23 as shown in FIG. 3 is uneasy to control, the path for spot welding is a rotary and twisting one; a product generally can not render a space xe2x80x9caxe2x80x9d between two spots straddling the joint equal to another space xe2x80x9cbxe2x80x9d between further two spots straddling the joint, neither render the space xe2x80x9ccxe2x80x9d of a spot from the joint line equal to another space xe2x80x9cdxe2x80x9d of a neighboring spot from the joint line. Thereby, viewing at an enlarged area as shown, it is evident to see that the edges of the engaging belt 22 are upwardly bent, for a shorter paper to be fed, the error of feeding is within the tolerance, while for a longer paper such as of 10 m, the tolerance is only 1 mm, accumulation of errors will make evident inaccuracy of the fed paper. Elements of the roller are plural; this can increase cost and inconvenience of production. (Note: paper feeding is run repeatedly forward and backward in a rotational way, the teeth are rough and accuracy is inferior, the rotational inertia will make error of size).
The present invention has a main object to provide a method for manufacturing a roller shaft of a computer character-cutting device and to the roller shaft itself.
The present invention has a secondary object to provide a method for manufacturing a roller shaft of a computer character-cutting device and to the roller shaft itself of which the novel structure makes the roller shaft more accurate in paper feeding, and can have a smaller tolerance.
To get the object, the present invention wraps an engaging belt having on the surface thereof etched tooth grains over a roller shaft, and then laser welding is processed at its joint. Laser welding creates high temperature to melt the engaging belt, and the melting spots on the engaging belt are leveled, so that the engaging belt is integrally molten into the roller shaft to largely reduce steps and cost of production.
The present invention will be apparent after reading the detailed description of the preferred embodiment thereof in reference to the accompanying drawings.